PSOM Reprogram Mileage Reading
 

I've seen the information about recalibrating the PSOM for tire size etc. Does anyone have the information on how to reprogram the actual mileage reading? I have a different one that I'd like to use, but would like to program the actual mileage, so that it matches the truck.

Subscribe.

I am pretty sure that is Not a viable option. If it was you could simply reset your 399,999 cluster to 40,000 and lie about the milage on the truck

Is there a way we can have it sent off to have it done?

Anybody with a EPROM burner can just copy the mileage from one board to the other boards EEPROM chip. It is not rocket science.
Or you can buy a eprom burner off of ebay and do it yourself.
Or you can un-solder the EEPROM and solder it into the other board with or without a soldered socket.

I'm not familiar with eproms, so which part do we un-solder?

You might want to read through these links:
https://www.ford-trucks.com/forums/1...r-display.html

https://www.ford-trucks.com/forums/1...splay-fix.html

The red square is the EEPROM chip.
Attachment 279742

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Subford.
I just swapped in a 93 lightning 120mph speedo into my 92 f150 90mph.
Is it still possible to swap the 92 eeprom chip into the lightning psom and it still work correctly and keep my org mileage?
The threads mention the eeprom keeping the mileage and gear ratio, i just want to make sure the speedo isn't affected.

I think the program in the large chip is what decides on how far to drive the needle. But this is just a guess. The EEPROM chip is just an information storage device for when the power is off.

The EEPROM does have needle movement data stored in it for upper scale and lower scale needle calibration. I found out about that after a EEPROM swap on my E350 Bus. Had to copy only the milage data over to the other EEPROM along with the pinion ratio factor too, left all other data same for that speedometer.

As for resetting mileage to a specific number, I have not figured out the data encoding parity, so no go(yet)on changing mileage beyond swapping data sets around.

I would have thought that Ford dealers would have had a way to do this, if this part had to be replaced when the trucks were fairly new.

Whats this all about?

It looks like he is sending a false signal so it thinks its being driven. That would work to add miles but not take them off. It would take a while to have it come back around and up to the correct mileage doing that. From what I understand it rolls over to zero again after 400k.

The idea of swapping the EEPROM has me worried I'll damage the parts I'm working with. I've never used a burner for them, but am curious to see how that works.

I'm also swapping to a Lightning speedometer.